Fifth generation (5G) wireless refers to a proposed telecommunications standard that is set to replace the current fourth generation (4G) telecommunications standard. 5G aims to offer improved network capability including faster download speeds, greater bandwidth, spectral efficiency, lower latency, etc. The 5G standard will use a high frequency/short wavelength frequency spectrum, e.g., in the range of 20 GHz-60 GHz, which corresponds to wavelengths in the range of 5 mm-15 mm. These short wavelengths present unique design challenges with respect to the base station equipment that is used to transmit and receive the RF signals.
Phased antenna arrays generally refer to communication systems that use a plurality of antennas (two or more) and phase shifting to transmit and receive RF signals. Phased antenna arrays offer numerous advantages over single antenna systems, such as high gain, directional steerability, and simultaneous communication. Currently, there are no commercially available 5G mmW (millimeter wavelength) phased antenna array systems. One notable design challenge with respect to 5G mmW phased antenna array systems is that the spacing between antenna elements must be correlated to the wavelength of the RF signal, typically ½ of the wavelength. In the case of 5G systems, this means that the antennas must be spaced apart from one another in the range of 2 mm 7 mm, which places a premium on space efficiency. To this end, amplifier devices that can operate at very high frequencies and offer a small footprint are preferred. One amplifier device that is able to operate at very high frequencies and has a small footprint is a III-V semiconductor device, such as a GaN (gallium arsenide) based HEMT (high-electron-mobility Field Effect Transistor) amplifier device. III-V semiconductor devices are typically normally-on devices. That is, these devices have a self-conducting channel that is present without any gate bias. Therefore, these normally-on devices must be controlled by circuitry that is capable of generating negative voltages to turn the device off. In the context of 5G mmW (millimeter wavelength) phased antenna array systems, GaN based HEMT devices, while promising, introduce unique and currently unsolved challenges with respect to gate biasing, compensation for dynamic drain current effects, power back-off, etc.